Case shift mechanism for typewriting machines



July 2, 1940. H. A. AVERY El AL CASE SHIFT MECHANISM FOR TYPEWRIT ING MACHINES Original Filed Feb. 3, 1939 2 Sheets-Sheet 1 y 5% 5,; MM

' XTT'oR EY July 2, 1940. H. A. AVERY ET AL CASE SHIFT IECHANISM FOR TYPEWRITING MACHINES Original Filed Feb. 3, 1939 2 Sheets-Sheet 2 Patented July 2, 1940 CASE SHIFT MECHANISM F OR- TYPE- WRITING MACHINES Henry Allen Avery and Joseph, P. 'Barkdoll; Groton, N. Y., assignors to L. O. Smith & Corona Typewriters, Inc., Syracuse, N. Y., a corporation of New York Original application February 3, 193 9, Serial No. 254,362. Divided and this application March 15, 1939, Serial No. 261,880

3 Claims. (Cl. 197-43) 1 The invention relates to improvements in case shift mechanisms for typewriting machines and its principal purposes are to provide a simple, inexpensive and effective construction whereby 6 case change may be effected in such machines; to

provide a simple, light, compact and sturdy construction whereby case change by shifting the platen carriage may be effected and which is especially suitable for small and light portable 1 typewriting machines of the semi-'front-strike variety; and to provide improved means for actuating and determining the shift limits of a case shift frame.

To the foregoing and other ends which will hereinafter appear, the invention consists in combinations of devices, arrangements of parts, and features of construction which will be described hereinafter and particularly pointed out in the appended claims.

In the drawings, in which the invention is illustrated in a preferred form embodied in a small, flat, portable typewriting machine of the semi-front strike or three-quarter strike variety,

Fig. 1 is a vertical, medial, longitudinal sec- 5 tional view of the machine on the line ll of Fig. 2 is a detail vertical, transverse sectional view taken on the line 2-2 of Fig. 1 and showing certain only of the parts illustrated in Fig. 1;

80 Fig. 3 is a detail view showing in side elevation parts of the main and case shift frames of the machine as viewed from the left-hand side of the machine;

Fig. 4 is a detail sectional view taken on the 86 line 4-4 of Fig. 1; v

Fig. 5 is a fragmentary top plan view of the machine showing the forward portion of the machine;

Fig. 6 is a fragmentary bottom plan view show- 40 ing the rear portion of the machine;

Fig. 7 is a detail rear elevation of the machine showing parts of the.machine;.and

Figs. 8 and 9 are detail sectional views on an enlarged scale taken on the line P-P of Fig. 3

and illustrating the two pivotal connections between -the main and case shift frames of the machine. I

This application is a: division of our co-pending 50 application filed Feb. 3, 1939, Serial No. 254,362.

The invention is shown embodied in a very small and flat portable type writing machine of very light weight, the machine being drawn to full scale in Figs. 1 to 7. Only so much of said 66 machine as is necessary to a full understanding of the present invention is shown andwill be hereinafter specifically described.

The main frame of the machine comprises a pair of upstanding but low and short sheet metal 5 side walls or plates l0, and an upstanding sheet 6 metal partition plate orcross-wali l l. The'crosswall inclines upward and rearward at an angle of forty (40) degrees to the horizontal and is provided along its lower edge with an integral horizontal forwardly 'extendingfiange l I located 10 closely adjacent the bottom edges of the sidewalls ID. The side walls iii aregreatly reducedin height at their rear ends for aboutfone-quarter of their length, and cross-wall ll connects the rear ends of the higher portions or the side walls 18 immediately forward of said reducedirea'r' end portions of the side walls. Wall extends u'pward about one-half the maximum heightof the side wallslli. Wall II is formedat each-end with a pair of lugs I2, and flange I lfon saidfwall is 90 formed at each end with a lug 12 which lugs l2 and [2 extend outward through apertures in the adjacent side wall I0 and are headed over .against the outer face'of the side wall to rigidly tie the three frame walls together.

Wall II and its flange H are located in the rear half of the main frame. Walls In are provided along their lower edgeswith horizontal inwardly projecting stiffening flanges III! extending from their front ends substantially to flange II of wall ll. Walls III are provided along their lower edges in rear of flanges Ill with horizontal inwardly projecting stiffening flanges I0 which flanges ill extend to the rear ends of said walls It and preferably increase in width toward their front ends, as shown. Each flange I li has a slightly upwardly offset forward end portion abutting flatwise the bottom face of flange ll and spot-welded to said flange I I at points I3.

The case shift frame of the machine comprises a sheet metal carriage bed and three sheet metal brackets detachably but rigidly held to the bed. The carriage bed It is formed along its longitudinal edges with integral upstandingraceway flanges l4. One of said three brackets is a bracket I5 located substantially midway the ends of the bed and substantially mediallyof the sides of the machine, and the other two of said brackets are a pair of brackets I6 located: adjacent opposite ends of thebed and adjacentlopposite sides of the machine. Bracket I5 is rigidly but detachably held at its rear end to the carriage bed It at the under face of the bedby four screws i'l. Each of the brackets I6 is rigidly but detachably held to the carriage bed at the under face of the bed by a pair of screws II.

A pair of pintle or pivot screws It and II, for pivotaily supporting the shift frame, extend horisontally transversely of the machine in axial register through axially aligned threaded apertures II and 22 formed in the respective side walls III of the main frame adjacent the upper rear corners of said side walls. Pintle screw is is adjustably threaded through aperture II in the left-hand side wall of the main frame, and pintle screw II is adjustably threaded through aperture 22 in the right-hand side wall of the main frame,

the outer end of each screw being slotted to re-- ceive a screwdriver. Lock nuts 23, threaded on the outer endsof the pintle screws against the outer faces of the side walls ll of the main frame, serve to releasably lock the pintle screws in adjusted position against accidental turning.

Each bracket member I of the shift frame is formed with an integral pendent pivot earv ll' disposed flatwise in a vertical plane extendin fore-and-aft of the machine, the two pivot ears being located inside the side walls I I adjacent opposite sides of the machine and spaced apart sufficiently less than said side walls to permit of adjustment of the shift frame transversely of the machine. Ear it of the right-hand one of the brackets ii is provided with a screw-threaded cylindrical bearing aperture 25 through which is screwed the pintle screw II, and ear ll of the left-hand bracket It is provided with a nonthreaded cylindrical bearing aperture 24 axially aligned with aperture 25 and through which extends an elongated reduced non-threaded inner pintle end portion I! of pintle screw II. The sev'eral screw threads are of fine pitch, and ear it of left-hand bracket I6 is slidable on pintle v portion w longitudinally of the latter.

A sheet metal bracket 26, located medially of the sides of the machine behind cross-wall ll of the main frame, is detachably but rigidly held to the wall ii at the rear face of said wall by screws 21 and is provided with two superposed, vertically spaced, rearwardiy extending lugs a and 29. Shift frame bracket member II has a narrow forward integral end portion II which is located medially of. the sides of the machine and extends between, and is movable up and down between, lugs II and 29 on bracket 28.

End portion iiof shift frame member II is normally seated on the upper end of an adjust able stop screw 30 threaded upward through the lower lug I! on bracket 26, such seating determining the lower-case. printing position of the shift frame. Rocking of the shift frame from lower-case printing position is limited, to arrest the shiftframeinupper-case printing position, by means of an adjustable stop screw Ii threaded upward through portion ll of shift frame member II for engagement of the upper end of screw 3| with the'under face of the upper stop lug 28 on bracket 26 upon upward swinging of member II. Screws II and II are located one behind the other medially of the sides of the machine with their slotted heads at the lower ends of the screws and accessible from the bottom of the main frame for adjustment of the screws. Suitable lock nuts 32 (Fig. 1) are preferably threaded on the screws 30 and II so as to be accessible from the bottom of the main frame, as shown.

The shift frame member I5 is bent, forwardly of the carriage bed and about midway the front and rear ends of said member, along a line extending transversely of the machine in such manner as to' support the carriage bed with the plane of its bottom face substantially parallel to the plane of the main frame cross-wall II, with the raceway flanges l4 of the carriagebed extending generally upward and forward from the bottom of the bed and with the forward part of said member ll extending substantially horizontally forward from said line of bend, all as shown more particularly in Fig. 1, when said member II is seated at its front end on stop screw II in the lower-case printing position of the shift frame.

A suitable platen carriage 33, having the usual roller platen l4 journalled therein in the usual manner, is supported by the forwardly and downwardly tilted bed l4 to travel transversely of the machine over the low rear part of the main frame, the tilted bed supporting the carriage in correspondingly forwardly and downwardly tilted relation to the main frame with the platen above and forward of the pivotal axis of the shift frame and above the low rear part of the main frame. The carriage is provided with suitable raceway flanges II opposed to raceway flanges H of bed I4 and travels, as is common in the art and as indicated in Figs. 1 and 3, on suitable ball bearings 35.

The machine is provided with the ordinary arcuate type bar segment I. in the usual slots of which on the usual arcuate pivot wire 31 carried by the segment are pivoted the type bars of the usual set of type bars each carrying the usual two types. One central type bar and one side type bar are shown, said type bars being designated by the reference numeral 38, and each type bar carrying a lower-case type II and an upper-case type 4|, the segment supporting the type bars as usual to print at a common printing point medially of the sides of the machine. In the machine shown, the segment is secured by screws 4| to the front face of cross-wall ll of the main frame medially of the sides of the machine, for striking of the type bars to a printing point which is located as is indicated in Fig. l, and as is common in machines of the semifront-strike or three-quarter-strike variety, on the upper front portion or quarter of the platen. The pivot wire 31 in the upwardly and rearwardly inclined segment it lies in a plane parallel to that of wall ll. tend upward and forward from their pivots and are normally supported adjacent their typecarrying ends by a type bar rest 42. Rest 42 extends across the main frame about mid-length of the machine and at the top of the main frame and is secured at its ends to sidewalls It of the main frame by screws 43. Any suitable gieans may be employed for actuating the type ars.

The shift frame and the platen carriage with its platen are constantly biased by reason of preponderance of weight thereof forward of the pivotal axis of the shift frame to gravitate to normal lower-case printing position. Duplicate optionally operable means provided for shifting the shift frame to position platen 34 in the uppercase printing position of the latter indicated in dotted lines in Fig. 1 will now be described.

Extending fore-and-aft of the machine adjacent opposite sides of the machine are two optionally operable shift key levers of beilcrank form each having a forwardly extending arm 44 and a pendent downwardly and rearwardly extending arm 45, the forwardly extending arm 44 of each said key lever extending forward beyond The type bars normally exthe front end of themain frame and carrying slots 49 lying in parallel vertical planes which extend fore-and-aft of the machine. Extending longitudinally throughsaid bar horizontally and transversely of the machine are two straight and parallel pivot or fulcrum wires and 5|. The wire 50 crosses both slots 49 adjacent the upper ends of the slots, and wire 5| crosses both slots 49 adjacent the lower ends of the slots.

The twoshift key levers are formed of sheet metal and pivotally mounted on the higher wire 50 with each lever engaged in and guided by a different one of said slots 49. Two fore-and-aft extending bellcrank sub-levers located between walls l0 adjacent opposite sides of the machine and formed of sheet metal are pivotally mounted on the lower wire 5| with each said sub-lever engaged in and guided by a different one of said slots 49 in fulcrum bar 41. Each fore-and-aft extending sub-lever has an upwardly and forwardly extending front arm 52 and a rearwardly extending arm 53. Lever arms 53 extend through and are movable up and down in slots 54 in crosswall II of the main frame, each said lever arm being formed behind said wall with a forked rear end portion 53' in which is engaged the outer end of the outer arm of one of a pair of sheet metal sub-levers 55 of the first order which extend transversely of the machine behind wall I I. Each sub-lever 55 is engaged at its inner end under the forward end portion I5 of shift frame member l5 substantially at the medial fore-andaft center line of the machine and is fulcrumed intermediate its ends on one of two horizontal pivot screws 56 extending fore-and-aft of the machine and held to lugs 51 formed integrally with wall ll.

Extending horizontally and transversely of the machine between walls I 0, adjacent the tops of said walls and forward of fulcrum bar 41, is a return stop device 58 for the shift key levers, said device extending over the key-carrying arms 44 of the shift key levers and being rigidly but detachably held to walls II) by screws 59. Each key lever and its associated fore-and-aft extending sub-lever are connected by a coiled return spring 60 of the tension pull type, the spring being' connected at its ends to said levers to the rear of the lever fulcrums to maintain arm 52 constantly engaged behind arm 45 and to normally urge the connected key lever, fore-and-aft-extending sublever, and transversely extending sub-lever into the relative positions thereof shown in the drawings. In this normal positional arrangement of the connected levers, the arms 44 of the shift key levers are urged upward against the under side of stop 58, and the inner ends of levers 55 are lowered far enough for part l5 of shift frame member i5 to seat on top of stop screw 30.

By depressing either shift key 46 the shift frame may be rocked upward and rearward until stop screw 3| engages under stop 28 to thereby position platen 34 in the upper-case printing position of the latter indicated in dotted lines in Fig. 1. Each wall Ill of the main frame is formed at its front end with an upstanding lug 6i extending inward from said wall transversely of the machine and provided with a vertical guide slot 62 for the forward arm 44 of the adjacent shift key lever. Slot 82 in each lug 6| is widened in the lower portion thereof at one side thereof to provide a downwardly facing stop or looking shoulder 63. Arm 44 of each key lever is sufllciently flexible laterally to permit engagement thereof under the associated stop shoulder 83 after full depression of said key lever, to thereby permit locking of the shift frame in upper-case Position when desired.

It will be observed that an extremely light, compact and inexpensive construction is provided in which, nevertheless, a predetermined working relation will be maintained between the main and shift frames and between the platen carriage shift frame and the type bar segment. It will also be observed that both-frames are of simple, light and inexpensive construction; that the shift frame may be readily assembled on and removed from the main frame; that the shift frame may be adjusted axially by simply turning the pintle screw 20 which will maintain the adjustment; and that the key-actuated means for rocking the shift frame is so associated with said frame that said frame is rockable by power applied midway its ends.

What we claim is:

1. In a visible writing typewriting machine, the combination of a main frame, a platen, a platen carriage on which the platen is mounted, a shift frame supporting the'carriage to travel transversely of the main frame and pivotally connected to the main frame at opposite sides of the fore-and-aft medial line of. the main frame for oscillation of the shift frame about a fixed horizontal axis extending transversely of the main frame, said shift frame including a member located medially of the sides of. the main frame and extending forwardly of the said axis, means on the main frame coactive with said member adjacent its forward end for limiting up and down movement of said member, said shift frame and carriage normally urged about the said axis in a direction to lower the forward end of said shift frame member to position the platen for lower case printing, transversely of the main frame and fulcrumed on the main frame to one side of said member to swing about a fixed axis extending fore-and-ai't of the main frame, the inner end of said'transversely extending lever being engageable under the forward end of said member, a lever of the first order extending fore-and-aft of the main frame adjacent one side of the latter and fulcrumed on'said frame to swing about a fixed horizontal axis extending transversely of the main frame, a fore-and-aft extending shift key carrying lever of the first order fulcrumed on the main frame adjacent said side of. the main frame to swing about a fixed horizontal axis parallel to that of the second-mentioned lever and having its rear arm engaged under the forward arm of said second-mentioned lever to rock the latter lever, said second-mentioned lever having its rear end engaged with the outer end of the transversely extending lever to rock the latter to position the platen for upper case printing, and type bars each having lower and upper case types and mounted on the main frame for printing coaction of said lower and upper case types with the front portion of, the platen in the respective lower and upper case printing positions of the platen.

a lever of the first order extending 2. In a typewriting machine, a main frame, a fore-and-aft extending shift key lever of the first order fuicrumed on the main frame adjacent one side of said frame to rock about an axis extending transversely of the main frame and carrying a shift key on its forwardly extending arm, a fore-and-aft extending sub-lever of the first order fulcrumed on said frame to rock about an axis parallel to that of the key lever and having its forward arm engaged over the other arm of the key-carrying arm of the key lever is elevated, a stop on the main frame engageable by one of said levers to determine said idle position, a sublever of the first order extending transversely of the main frame and fulcrumed on the main frame to rock about an axis extending foreand-aft of the main frame, the outer arm of said transversely extending sub-lever being pivotally connected to the rear arm of the fore-and-aft extending sub-lever to move up and downwith said rear arm, and a shift frame pivoted on the main frame to rock about an axis extending transversely of the main frame and normally gravitate to a lower case printing position in which the inner end of said transversely extending sublever is engageable thereunder and operable thereon to rock said shift frame into upper case a,aoe,o1'r v printing position upon depression of the min key carrying arm of the shift key lever.

3. A typewriting machine having a main frame, a shift frame supported adjacent opposite sides of the main frame for case changing movement from a normal lowerprinting position of the shift frame, a platen-. carriage mounted on the shift frame, and means for shifting said shift 7 frame to upper case printing position, said shifting means comprising a lever of the first order extending transversely of the main frame and fulcrumed thereon to rock in a vertical plane extending transversely of the machine, said lever having its inner arm engaged with said shift frame substantially medially of the sides of the main frame to shift the shift frame into position for upper case printing, a shift key lever of the first order extending fore-and-aft of the main frame and fulcrumed thereon to rock in a vertical plane, and a fore-and-aft extending sub-lever of the first order interposed between said two levers and fulcrumed on the main frame to rock in a vertical plane and having its forward arm engaged with the rear arm of said shift key lever and its rear arm engaged with the outer arm of said transversely extending lever to shift the shift frame into position for upper case printing upon depression of the forward arm of the shift key lever.

HENRY ALLEN AVERY. JOSEPH P. BARKDOLL. 

